1. Field
The invention is in the field of devices for measuring the liquid level in a liquid reservoir such as measuring the level of oil in the crankcase of an engine or the level of transmission fluid in a transmission.
2. State of the Art
U.S. Pat. No. 4,649,746 discloses a device for measuring the liquid level in a liquid reservoir and shows as an example the device used to measure the level of oil in the crankcase of an engine. The device takes the place of the normal dipstick commonly used to measure oil level and fits into the engine dipstick tube in place of the dipstick. The device has a plunger extending from the top thereof which is depressed by the user, the extent to which the plunger can be depressed indicating the level of the oil in the engine. This gives an easy means for measuring oil level and avoids having to remove and clean the dipstick. It is also much easier to read than dipsticks generally are.
While the device of U.S. Pat. No. 4,649,746 operates very well and has a number of advantages over the normal dipstick, practically, most engines require different length dipsticks and thus, require different lengths for the dipstick replacement device of the patent. This creates a problem because in the automotive after-market, products must fit a number of different vehicles as the inventory required to stock a size for each vehicle is much too large for most dealers to handle. Thus, to make the device of U.S. Pat. No. 4,649,746 practical for the automotive after-market, it is necessary that the device be adjustable over at least a limited range of lengths so that a single device may be adjusted to fit a variety of different engines.